Let x be the height of the point at which the tree snapped, as shown in the figure above..
The length of the portion touching the ground will be 12-x ft.
Now Applying Pythagoras Theorem, (12-x)2 – x2 = 42
On simplifying, 144-24x +x2 –x2 = 16
Or, 24x = 128
x= 
ft
= 5 ft 4 in
****